It has been claimed that it can be beneficial in treating a number of health care issues including pain, symptoms of cancer and stress and anxiety.

But what is cannabis oil made from and what is it used for? Here's everything you need to know.

What is cannabis oil?

Cannabis oil is thick and sticky substance extracted from the leaves and flowers of the hemp plant. It is also refereed to as CBD (due to the strain it is made from), full extract cannabis oil (FECO) and hash oil.

According to macmillan.org.uk , a cannabis plant produces a resin (sticky flammable organic, insoluble in water) that contains various substances, these are known as 'cannabinoids'.

The two main types of cannabinoids are:

Delta-9-tetrahydrocannabidiol (THC) - illegal in the UK and not used to make cannabis oil

Cannabidiol (CBD)

According to cannabis oil manufacturer hertshemp.com, this is the distinction between THC and CBD cannabinoids:

Tetrahydrocannabinol (THC)

THC is the most abundant constituent of the cannabis plant, and the most well known. THC is the intoxicating and psychoactive substance that is responsible for causing the marijuana high.

It is considered a controlled substance, and is therefore illegal.

Cannabidiol (CBD)

The second most abundant compound is Cannabidiol, more commonly known as CBD. This is a non-psychoactive substance, typically representing about 40% of the Cannabinoids in the Cannabis plant. And it's the effect of this particular Cannabinoid, CBD that is currently being researched in many studies all over the world.

Why is cannabis oil legal?

CBD is not considered a controlled substance, and is therefore 100% legal.

It is what cannabis oils being sold in the UK are made from.

What can it be used for?

It can be beneficial for people who suffer from stress, anxiety, depression or lack of sleep. It has also been suggested that it can be used to help alleviate the pain of cancer patience.

Macmillan.org.uk said: "There are side effects of using cannabis oil. Cannabinoids can increase your heart rate, cause dizziness, hallucinations, paranoia and make you feel ‘stoned’. They may also interact with other drugs."

It has also been claimed cannabis oil can treat symptoms of Alzheimer’s Disease, Parkinson’s Disease and MS.

Where can I buy it?

(Image: Holland and Barrett)

Holland and Barrett is selling Jacob Hooy CBD+ Oil 2.75% 10ml for £9.49, (it's currently on offer, the usual RRP is £19.99). Since stocking the product at the high street store, sales of Jacob Hooy have shot up 37 per cent.

It began selling the product at the beginning of the year, it is said to be made with cold-pressed hemp seeds. Each 10ml bottle contains approximately 240 drops.

The advise on the bottle's packaging reads: "CBD+ Oil has a 'distinctive' taste - have a small drink of water after taking the oil and the taste will be gone within 30 seconds."

Users take it orally, by putting a few drops under the tongues 2-3 times a day. Leave the oil in the mouth for one minute before swallowing. The maximum dosage is 15 drops a day.

It has proved to be popular with customers, so much so that Holland and Barrett will be introducing four more CBD products to its range later on in the year.

Holland & Barrett said: “‘We have been surprised at the success and popularity of CBD oil since its launch. We are constantly looking to bring new and innovative ­products to market that help our customers.

“It is great to see in this instance that we can help with the demand.”